An unusual belt of molten rock Stretching more than 3,000 kilometers from British Columbia, Canada, to Sonora, Mexico, it has been identified by researchers at the University of Wyoming and caused a stir among the scientific community due to its mysterious origin, because It is not known why it melted.
The Rocky Belt runs through Idaho, Montana, Nevada, southeastern California and Arizona.
“What makes this interesting and mysterious is that this belt of igneous rocks is located much farther inland, far from the edge of the continent, and contains no evidence of volcanoes. In fact, all the melting of igneous rocks generated was originally found. Deep underground, five to ten miles below the surface. “
The mysterious melting of the earth’s crust
Chapman is the lead author of an article titled “The North American Anatomical Cordilian Belt,” which was published online in February in the magazine. Earth Science Reviews.
One of the clues to the origin of the volcanic belt is that the rocks were primarily formed 80 million to 50 million years ago, during a mountain building event called the Laramid Formation.
“The Laramide Mountain Range has created most of the major mountain ranges that we have in Wyoming, and the name actually comes from the Laramie Range,” says Chapman.
Although there are no igneous rocks of this type and age in these mountains, we suspect that the tectonic processes that created the mountains also contributed to the melting of the Earth’s crust.
What can dissolve rocks?
Researchers have developed several working hypotheses about why rocks have melted.
One hypothesis is that water infiltrated the deep crust. The geochemistry of these rocks indicates that the melting may have occurred at relatively low temperatures, below 800 ° C, which are extremely hot, but not hot enough to produce large quantities of magma. Water reduces the melting point of rocks, similar to the way salt reduces the melting point of ice, and can increase the amount of magma generated.
This work has implications for what causes rock amalgamation and where certain types of magma may be found.